Sputter coating power processing portion

A sputter coating apparatus power processing portion comprising a sputtering cathode to which a negative voltage is intermittently applied, wherein:

• the power processing portion comprises a first switching circuit, a second switching circuit, control means, and means for measuring at least one of a current, a voltage and a power for sputtering;
• the first and the second switching circuits are respectively formed of a semiconductor switching device and a protection circuit for protecting the device;
• the first switching circuit is connected in series between a negative pole of a sputtering power generating portion and the cathode;
• the second switching circuit is connected in series between the cathode and a DC power source other than the sputtering power generating portion, for supplying a positive potential to the cathode electrode;
• the control means is capable of controlling a turning-on time of at least 5 .mu.s for the first switching circuit and a turning-off time of at least 5 .mu.s for the first switching circuit, and wherein said control means is further capable of turning-on the second switching circuit for less than the time of turning-off the first switching circuit and within a range of from 1 .mu.s to 20 .mu.s when the first switching circuit is turned off;
• and
• the means for measuring at least one of a current, a voltage and a power for sputtering measures at least one of a current value, a voltage value and a power value effective for sputtering and compares the measured values with determined reference values to detect arcing.